The present invention relates to application level connection between a terminal of the microcomputer type and a portable electronic object such as a smart card, sometimes referred to as a “microcontroller card” or as an “integrated circuit card”, acting as a peripheral of the terminal.
At the application level, the interchange between a host station, such as a terminal, for hosting a smart card and the smart card takes place by means of Application Protocol Data Units (APDUs) which are commands transmitted by the terminal to the card and responses transmitted by the card to the terminal. The format of such commands and responses is defined at the application level by the ISO 7816-4 Standard and its appendices A and B for conveying protocol units using the half-duplex asynchronous transmission protocol in “T=0” characters or the half-duplex alternate transmission protocol in “T=1” blocks. The commands are always triggered by the terminal and the card must be of the pro-active type to transfer data on its own initiative to the terminal.
In addition, the “Universal Serial Bus Specification”, September 1998, defines a standardized universal serial bus (USB) for connecting a microcomputer (e.g. a personal computer (PC)) to peripherals. All data transfers between the microcomputer and a peripheral are triggered by the microcomputer, the peripheral always being the slave of the microcomputer, unlike a smart card relative to the terminal. All of the transactions made via the USB are effected by means of packets whose formats and sequencing are different from those of the commands and responses defined by the ISO 7816-4 Standard for smart cards.